1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device and a method of fabricating the same, and particularly, to an LCD device capable of preventing inferiority of a thin film transistor (TFT) due to a charging current difference by maintaining a charging current occurring from an odd numbered data line to be equal to a charging current occurring from an even numbered data line, and a method of fabricating the same.
2. Background of the Invention
A liquid crystal display (LCD) device is a transmissive flat panel display device, and is mainly applied to each kind of electronic devices such as a notebook computer, personal digital assistants (PDA), and a mobile phone. Recently, this LCD device is being actively practicalized much more than other flat display devices owing to its thin and light characteristic and high picture quality. As demands for high-definition televisions (HDTVs), digital televisions, and wall-mounted televisions are increased, research on an LCD device of a large area which can be applied to the TVs is actively ongoing.
Generally, LCD devices may be classified into several types according to a method of driving liquid crystal molecules. Nowadays, an active matrix TFT-LCD device is being mainly used owing to a fast response speed and less residual images.
FIG. 1 is a view schematically showing a structure of an LC panel 1 of a TFT-LCD device in accordance with the conventional art.
As shown in FIG. 1, a plurality of gate lines 3 and data lines 5 which define a plurality of pixels by being arranged in horizontal and vertical directions are formed on the LC panel 1. A thin film transistor (TFT) 7, a switching device is arranged in each pixel. When a scan signal is inputted to the TFT through the gate line 3, the TFT is switched to apply a signal inputted through the data line 5 to the pixel 9.
A gate driving portion 11 and a data driving portion 15 are arranged outside the LC panel 1. A plurality of gate driving circuits 12 are arranged at the gate driving potion 11, thereby inputting scan signals to the gate lines 3 through pads (not shown). This scan signal is applied to a gate electrode of the TFT 7 to activate a semiconductor layer of the TFT 7. A plurality of data driving circuits 16 are arranged at the data driving potion 15, thereby inputting image signals to the data lines 5 through pads (not shown). This image signal is applied to the pixel 9 through source and drain electrodes of the TFT 7 when the semiconductor layer has been activated (i.e., a channel has been formed at the semiconductor layer).
The pixel 9 is formed at an intersection between the gate line 3 and the data line 5, and is provided with one TFT 7. Accordingly, the pixels formed at each column is connected to one data line 5, and receive a signal applied through the corresponding data line 5.
In the conventional LCD device, one data line is connected to one pixel formed at each column. Accordingly, when ‘N’ data lines are arranged at the LC panel 1 and ‘n’ data lines are connected to the data driving circuits 16, ‘N/n’ data driving circuits 16 are totally required. Here, the data driving circuits 16 are expensive integrated circuits. Accordingly, when one data line is connected to one pixel formed at each column and a signal is applied to the data line, a large number of data driving circuits 16 are required. This may increase the fabrication costs of the LCD device.
Recently, as polycrystalline TFT techniques develop, there is implemented a structure of a system on panel (SOP) for integrating a data driving portion with pixels on an LC panel. In this structure, a large number of data driving circuits have to be formed in the LC panel. This may increase the fabrication costs, and increase an area of the LC panel.
In order to solve these problems, has been proposed an LCD device capable of sharing one data line by two pixels. In this LCD device, since two pixels are connected to one data line, two columns of pixels are connected to one data line.
However, this LCD device has the following problem.
When a threshold voltage difference occurs between a TFT of a pixel connected to an odd numbered data line and a TFT of a pixel connected to an even numbered data line at the time of fabricating the LCD device, a brightness of pixels connected to the odd numbered data line is different from a brightness of pixels connected to the even numbered data line. This may cause a picture quality to be deteriorated.
This problem may occur even when one data line is connected to one pixel. In this case, since one column of a pixel is connected to a corresponding data line, a brightness difference can not be easily recognized by a human's eyes. On the other hand, when one data line is shared by two pixels, a brightness difference occurs from two columns of pixels thus to be easily recognized by a human's eyes.